diff options
Diffstat (limited to 'drivers/cpuidle/cpuidle-calxeda.c')
| -rw-r--r-- | drivers/cpuidle/cpuidle-calxeda.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-calxeda.c b/drivers/cpuidle/cpuidle-calxeda.c new file mode 100644 index 00000000000..e1aab38c5a8 --- /dev/null +++ b/drivers/cpuidle/cpuidle-calxeda.c @@ -0,0 +1,161 @@ +/* + * Copyright 2012 Calxeda, Inc. + * + * Based on arch/arm/plat-mxc/cpuidle.c: + * Copyright 2012 Freescale Semiconductor, Inc. + * Copyright 2012 Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/cpuidle.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/time.h> +#include <linux/delay.h> +#include <linux/suspend.h> +#include <asm/cpuidle.h> +#include <asm/proc-fns.h> +#include <asm/smp_scu.h> +#include <asm/suspend.h> +#include <asm/cacheflush.h> +#include <asm/cp15.h> + +extern void highbank_set_cpu_jump(int cpu, void *jump_addr); +extern void *scu_base_addr; + +static struct cpuidle_device __percpu *calxeda_idle_cpuidle_devices; + +static inline unsigned int get_auxcr(void) +{ + unsigned int val; + asm("mrc p15, 0, %0, c1, c0, 1 @ get AUXCR" : "=r" (val) : : "cc"); + return val; +} + +static inline void set_auxcr(unsigned int val) +{ + asm volatile("mcr p15, 0, %0, c1, c0, 1 @ set AUXCR" + : : "r" (val) : "cc"); + isb(); +} + +static noinline void calxeda_idle_restore(void) +{ + set_cr(get_cr() | CR_C); + set_auxcr(get_auxcr() | 0x40); + scu_power_mode(scu_base_addr, SCU_PM_NORMAL); +} + +static int calxeda_idle_finish(unsigned long val) +{ + /* Already flushed cache, but do it again as the outer cache functions + * dirty the cache with spinlocks */ + flush_cache_all(); + + set_auxcr(get_auxcr() & ~0x40); + set_cr(get_cr() & ~CR_C); + + scu_power_mode(scu_base_addr, SCU_PM_DORMANT); + + cpu_do_idle(); + + /* Restore things if we didn't enter power-gating */ + calxeda_idle_restore(); + return 1; +} + +static int calxeda_pwrdown_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + highbank_set_cpu_jump(smp_processor_id(), cpu_resume); + cpu_suspend(0, calxeda_idle_finish); + return index; +} + +static void calxeda_idle_cpuidle_devices_uninit(void) +{ + int i; + struct cpuidle_device *dev; + + for_each_possible_cpu(i) { + dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, i); + cpuidle_unregister_device(dev); + } + + free_percpu(calxeda_idle_cpuidle_devices); +} + +static struct cpuidle_driver calxeda_idle_driver = { + .name = "calxeda_idle", + .en_core_tk_irqen = 1, + .states = { + ARM_CPUIDLE_WFI_STATE, + { + .name = "PG", + .desc = "Power Gate", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 30, + .power_usage = 50, + .target_residency = 200, + .enter = calxeda_pwrdown_idle, + }, + }, + .state_count = 2, +}; + +static int __init calxeda_cpuidle_init(void) +{ + int cpu_id; + int ret; + struct cpuidle_device *dev; + struct cpuidle_driver *drv = &calxeda_idle_driver; + + if (!of_machine_is_compatible("calxeda,highbank")) + return -ENODEV; + + ret = cpuidle_register_driver(drv); + if (ret) + return ret; + + calxeda_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device); + if (calxeda_idle_cpuidle_devices == NULL) { + ret = -ENOMEM; + goto unregister_drv; + } + + /* initialize state data for each cpuidle_device */ + for_each_possible_cpu(cpu_id) { + dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, cpu_id); + dev->cpu = cpu_id; + dev->state_count = drv->state_count; + + ret = cpuidle_register_device(dev); + if (ret) { + pr_err("Failed to register cpu %u, error: %d\n", + cpu_id, ret); + goto uninit; + } + } + + return 0; + +uninit: + calxeda_idle_cpuidle_devices_uninit(); +unregister_drv: + cpuidle_unregister_driver(drv); + return ret; +} +module_init(calxeda_cpuidle_init); |